JPH11104067A - Bending mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bending mechanism capable of bending a desired part to be bent, such as the end of an endoscope, the bending part of the mechanism having sufficient flexibility to provide a large bending angle. SOLUTION: In a bending mechanism, a fiberscope 1 whose end serves as a swing part 1a has shape-memory alloy coils 2a, 2b disposed at the first end of the swing part 1a in such a way as to be elongated to positions that are in axial symmetry with respect to the fiberscope 1, each of the shape memory alloy coils 2a, 2b storing a closely wound condition. The ends of the coils 2a, 2b are connected to both ends 4a, 4b of a movable piece 4, and both ends 4a, 4b of the movable piece 4 to which the coils 2a, 2b are connected can swing about the center of the movable piece 4. The other ends of the coils 2a, 2b are connected to a fixed member 5. Towing wires 3a, 3b are each connected at one end to the end 4a (4b) of the movable piece 4 and at the other end to an end ring 6 placed at the end of the fiberscope 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending mechanism capable of bending a desired bending portion, and more particularly to a bending mechanism suitable for use in a small diameter device such as a medical endoscope.

[0002]

2. Description of the Related Art As an endoscope having a bending mechanism, for example, JP-A-63-136014 describes a large intestine endoscope to which an active bending device is applied. It is configured as follows. A plurality of segments are arranged in series, and each segment has a coil spring covered by a cylindrical exterior as a central skeleton, and flanges are provided at both ends thereof, and these are covered with a flexible jacket. Then, in the space between the outer surface of the coil spring and the outer cover, the shape memory alloy material, which is in a tightly wound state at a temperature equal to or higher than the transformation point, is stretched and deformed at axially symmetric positions on both sides of the coil spring. Books are arranged as a set.

[0003] In the endoscope configured as described above,
By heating one of the two sets of shape memory alloy materials, the shape memory alloy material on the heated side contracts and bends. When the heating is stopped, the shape memory alloy material loses the contraction force and returns to the expanded state due to the elastic force of the coil spring.

[0004]

However, in the above configuration, a coil spring is required to restore the shape memory alloy material to its original extended state, and each segment includes the shape memory alloy material, the coil spring, and the like. Thus, the rigidity of the segment portion increases. In the above configuration, since the segment portion itself is bent, there is a problem that it is difficult to obtain a large bending angle because of the rigidity of the segment portion.

Accordingly, the present invention provides a bending mechanism capable of bending a desired bending portion such as the endoscope end, wherein the bending portion has sufficient flexibility and a large bending angle can be obtained. The purpose is to:

[0006]

According to the present invention, there is provided a bending mechanism including a long body having a bending portion and two sets provided on one end side of the bending portion and arranged axially symmetric about the long body. A shape memory member, and a movable piece that is connected and connected to each of the two sets of shape memory members and that is swingably provided around a center between the two sets of shape memory members,
A fixed member connected to the other end of the pair of shape memory members and immovable with respect to the elongated body, one end connected to the movable piece, and the other end connected to the other end side of the bent portion through the bent portion; And a drawn pulling wire.

In the bending mechanism configured as described above, since only a pulling wire exists at the bending portion,
The bent portion has low rigidity and high flexibility, so that it can be easily bent, and the bent portion can obtain a large bending angle.

The shape memory member only needs to be able to pull the pulling wire through the movable piece.
Although there is no particular limitation such as the direction), for example, when used for a long body having a small diameter such as an endoscope, a shape memory alloy is preferable in terms of a large output volume ratio and the like. When used, it is preferable to use a coil shape from the viewpoint that a large amount of displacement can be obtained. Regarding the directionality of shape recovery, a unidirectional shape memory material is more preferable in terms of stability at the time of shape recovery and repetition characteristics.

When a shape memory member that recovers shape in one direction is used, either a shape memory member that contracts by shape recovery or a shape memory member that expands by shape recovery can be used.

When a shape memory member that contracts due to shape recovery is used, a tensile force (compression force when viewed from a long body) is applied to a portion between the movable piece and the fixed member even in a normal state where the shape is not recovered. For example, in the case of a long body that is easily bent or broken like an endoscope, the long body may be bent or broken at a portion between the movable piece and the fixed member. Therefore, when using a shape memory member that contracts due to shape recovery, the shape recovery force of the shape memory member and the elastic force in normal times are weakened,
It is preferable that a reinforcing member is provided at the above-mentioned portion.
On the other hand, in the case of using a coil that expands due to shape recovery, a stretching force (tensile force as viewed from a long body) is applied to a portion between the movable piece and the fixed member, and the tensile force is not generated. Therefore, the portion between the movable piece and the fixed member does not bend. Therefore, as described above, it is not necessary to weaken the shape recovery force and the normal elastic force of the shape memory member, it is easy to obtain a large bending angle, and it is not necessary to provide a reinforcing member. Since the rigidity of the portion between the piece and the fixed member can be reduced, the flexibility of the portion between the movable piece and the fixed member can be increased, and also, since there is no reinforcing member, it is suitable for reducing the diameter. It is preferred.

When a shape memory member that expands due to shape recovery is used, a force in the compression direction is always applied to the shape memory member itself. Therefore, when the rigidity of the shape memory member itself is low, the shape memory member itself is subjected to shape recovery. It may bend in an unintended direction other than the deformation in the longitudinal direction.
Therefore, it is preferable to provide a guide member for suppressing the bending of the shape memory member in the longitudinal direction.

It is preferable that the guide member has rigidity enough to withstand the deformation force of the shape memory member and small rigidity so as not to impair the flexibility of the endoscope. Examples of the aspect include an aspect in which a shape memory member is inserted into a hollow tube and an aspect in which a core material is provided on an inner peripheral side, that is, a hollow portion when the shape memory member is a coil or a hollow member. can give.

When a shape memory alloy material is used for the shape memory member, the heating method may be a method of connecting a lead wire to both ends of the shape memory alloy material and heating by energization, or one end of the shape memory alloy material. There is no particular limitation on the method of providing an optical fiber or the like on the side and irradiating light from the optical fiber to heat, but by irradiating the light and heating, the shape memory is performed without using electricity. Since the alloy material can be heated, it is particularly suitable for medical endoscopes and the like.

[0014]

Embodiments of the present invention will be described below in detail. 1 and 2 show a swinging endoscope using the bending mechanism of the present invention. FIG. 1 is a longitudinal sectional view of the endoscope, and FIG. 2 is a sectional view taken along line AA ′ in FIG. Explaining with reference to the drawings, the oscillating endoscope mainly has an elongated fiberscope 1 at its center, and the distal end side is an oscillating portion 1a that performs a bending operation. On the base end side of the swing part 1a, coils 2a and 2b made of a shape memory member are provided at axially symmetric positions with respect to the fiber scope 1. The distal ends of the coils 2a and 2b made of the shape memory member are connected to the movable piece 4, respectively.
The two ends 4a and 4b, to which the coils 2a and 2b are connected, can swing about the center. The other ends of the coils 2 a and 2 b formed of the shape memory member are connected to a fixed member 5 that is immovable with respect to the fiberscope 1. Further, one end of each of the pulling wires 3a and 3b is connected to both ends 4a and 4b of the movable piece 4, and the other end is connected to a tip ring 6 provided at the tip of the fiberscope 1. In addition, the coil 2a made of a shape memory member,
Reference numeral 2b stores a tightly wound state, and is attached in an extended state at the time of attachment.

The bending operation of the bending mechanism constructed as described above will be described.
When the coil 2a is heated, the coil 2a contracts, the end 4a of the movable piece 4 to which the coil 2a is connected is moved toward the hand, the pulling wire 3a is pulled toward the hand, and the bent portion 1a is bent.
In addition, since the center of the movable piece 4 is set as a fulcrum, the other end 4b, which is symmetrical with the one end 4a, is moved to the distal end, and the coil 2b is extended to the distal end. become. When the heating of the coil 2a is stopped and the coil 2a is sufficiently cooled, the coils 2a, 2a
b) The elastic force of both becomes the same, and returns to the original position so as to be in a balanced state. The coils 2a,
If 2b is a coil that expands due to shape recovery, by recovering the shape of one, the movable one end on the heated side is moved to the tip side, whereby the other end is moved to the hand side. , Pull the pulling wire to the near side,
The bent portion 1a is bent.

In this embodiment, a case where a swinging endoscope is used as a long body is shown, but the long body is not limited to this, and may be used for a manipulator, a catheter, and the like. Can be. The elongated body may have flexibility at least at the bent portion, and may have flexibility over the entire length of the elongated body, and a part of the elongated body may be a bent portion. It may be one in which a non-flexible main body and a flexible bent portion are connected.

The movable piece is not particularly limited as long as the shape memory member can be connected to both ends, and both ends can swing about the center of the movable piece. It is preferable that the rigidity is large in order to efficiently transmit the force to the pulling wire and the other shape memory member. Specifically, stainless steel, various ceramic materials, and the like can be used as such a material.

The fixing member can be connected to the shape memory member and is not particularly limited as long as it is immovable with respect to the elongated body. In the case of having elasticity, however, the end of the shape memory member slightly moves, so that the shape restoring force acts on the movement, and a part thereof is lost. Therefore, in order to efficiently extract the shape recovery force of the shape memory member, it is preferable that the fixing member has high rigidity. Specifically, stainless steel, various ceramic materials, and the like can be used as such a material.

The pulling wire may be any wire that can transmit the pulling by the drive unit to the endoscope and can withstand the tension generated at that time. However, in order to transmit the traction by the drive unit to the endoscope without waste, it is preferable that elastic extension is small, and from the viewpoint of space, a thin and large tensile strength is preferable. Ultrafine wires made of metal such as tungsten can be used.

[0020]

Embodiment 1 A specific embodiment will be described below. This embodiment shows an example in which the bending mechanism of the present invention is applied to a swinging endoscope. FIG. 1 is a longitudinal sectional view of a swinging endoscope according to the present embodiment. FIG. 2 is a sectional view taken along line AA ′ in FIG. More specifically, according to the drawings, the swinging endoscope mainly includes a fiberscope 1 including an image guide and a light guide.
Is a swinging portion 1a, and the swinging portion 1a
On the base end side, shape memory alloy coils 2a and 2b are provided at axially symmetric positions with respect to the fiber scope 1. The tip ends of the shape memory alloy coils 2a, 2b are connected to both ends 4a, 4b of the movable piece 4, respectively. The movable piece 4 is formed of a rectangular plate having an elliptical hole at the center. The fiber scope 1 is passed through the hole, and a portion corresponding to the center of the long side is connected to a movable piece fixing ring 7 provided on the outer peripheral side of the movable piece 4, and the shape memory alloy coils 2a, 2b are supported with the center of the long side as a fulcrum. Both ends 4a and 4b of the connected long side are swingable. The other ends of the shape memory alloy coils 2a and 2b are
Are connected to the fixed members 5 which are immovable with respect to. Further, the pulling wires 3a, 3b have one end on both ends 4a, 4b of the movable piece 4 and the other end on the fiberscope 1 respectively.
Are connected to a tip ring 6 which is provided at the tip of the fiber scope 1 and is immovable. These are covered with a jacket 10. The shape memory alloy coils 2a and 2b memorize the tightly wound state, and are attached in an extended state at the time of attachment.

[0021]

Embodiment 2 This embodiment shows another embodiment in which the bending mechanism of the present invention is applied to a swinging endoscope.
The configuration other than the shape memory alloy coils 2a and 2b, the guide member 8, and the movable single stop ring 9 is the same as that of the first embodiment. FIG. 3 is a longitudinal sectional view of the swinging endoscope of the present embodiment, and FIG. 4 is a sectional view taken along line BB 'in FIG. If described in detail according to the figure, the swinging endoscope is
A fiber scope 1 comprising an image guide and a light guide is provided at the center, and the tip side of the fiber scope 1 is a oscillating part 1a. 2a and 2b are provided at axially symmetric positions around the fiber scope 1. Stainless steel wires 8a and 8b as guide members are provided on the inner peripheral side of the shape memory alloy coils 2a and 2b, respectively, and both ends of the stainless wires 8a and 8b are connected to the movable piece 4. The movable piece 4 is formed of a rectangular plate having an elliptical hole at the center. The fiberscope 1 is passed through the hole, and the outer diameter of the movable piece 4 is slightly larger than the minor diameter of the elliptical hole of the movable piece 4. The movable piece stopper ring 9 is fixed to a position on the distal end side of the movable piece 4 of the fiberscope 1. Thereby, the movable piece 4 has both ends 4a of the long side to which the shape memory alloy coils 2a and 2b are connected with the center of the long side as a fulcrum.
4b is swingable. The other ends of the shape memory alloy coils 2a and 2b are respectively connected to fixing members 5 which are immovable with respect to the fiber scope 1.
Further, one end of each of the pulling wires 3a and 3b is
And the other end thereof is connected to a distal end ring 6 provided at the distal end of the fiber scope 1 so as to be immovable with respect to the fiber scope 1. The shape memory alloy coils 2a and 2b memorize the rough winding state, and are attached in a contracted state at the time of attachment. The stainless wires 8a and 8b as guide members do not hinder the operation of the movable piece 4. In the normal state, the connection is loosened.

With such a configuration, since the shape memory alloy coils 2a and 2b are applied with a force in the extending direction, the above-described reinforcing member is not required, and the stainless steel wire as the guide member is provided. 8a, 8b are connected to the movable piece 4, the fixed member 5, and the shape memory alloy coil 2a,
Since it is not necessary to connect both ends of the shape memory coil to the movable piece 4 and the fixed member 5 only by externally fitting the stainless wire 2b to the stainless wires 8a and 8b, the fabrication is easier than the configuration of the first embodiment. Is preferable.

[0023]

According to the bending mechanism of the present invention as described above, since the bending operation is performed by pulling the pulling wire, it is only necessary to provide the pulling wire at the bending portion, and the components at the bending portion are not required. Can be reduced. Therefore, since the rigidity of the bent portion can be reduced, an excellent effect that the bending angle of the bent portion can be increased can be obtained.

Further, since two sets of shape memory members are connected to both ends of the movable piece by using a movable piece that can swing at both ends with the central portion as a fulcrum, one of the shape memory members is restored to the shape. By doing so, the other shape memory member can be brought into a deformed state, and at normal times, that is, when the shape memory member is not recovered in shape, the two sets of shape memory members are restored to the original shape by force balance. Return to
Therefore, a coil spring or the like for returning the shape memory member to the original shape is not required. That is, since the number of constituent members can be reduced, an excellent effect that the endoscope can be easily reduced in diameter can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a swinging endoscope using a bending mechanism of the present invention.

FIG. 2 is a sectional view taken along line A-A 'in the embodiment of FIG.

FIG. 3 is a longitudinal sectional view of a swinging endoscope showing another embodiment of the bending mechanism of the present invention.

FIG. 4 is a sectional view taken along the line B-B 'in the embodiment of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fiber scope 2 Shape memory member 3 Pulling wire 4 Movable piece 5 Fixed member 6 Tip ring 7 Movable piece fixing ring 8 Guide member 9 Movable piece stopper ring 10 Jacket

Claims (4)

[Claims] An elongated body having a bent portion, two sets of shape memory members provided at one end of the bent portion and arranged axially symmetrically about the elongated body, and the two sets of shapes. The storage members are connected and connected to each other, and a movable piece provided so as to be swingable around the center between the two sets of shape memory members, and the other ends of the two sets of shape memory members are connected to each other to form an elongated shape. A bending member comprising: a fixed member that is immovable with respect to the body; and a pulling wire having one end connected to the movable piece and the other end connected to the other end of the bent portion through the bent portion. mechanism. 2. The shape memory member is a shape memory alloy coil that is elongated by shape recovery.
The bending mechanism as described. 3. The bending mechanism according to claim 2, further comprising a guide member for suppressing deformation of the shape memory alloy coil other than in the longitudinal direction. 4. An optical fiber for irradiating light for heating the shape memory member is provided on a fixing member side of each of the two sets of shape memory members. Bending mechanism.